Conventionally, identification symbols have been used on a variety of objects to provide a positive identification of the object that can be used e.g., in theft recovery, loss recovery, inventory control, tagging, tracking, and other applications as well. For example, automobiles are commonly provided with vehicle identification numbers (VINs) located in view near a bottom edge of the front windshield. The VIN is useful e.g., in conveying title, tracking, insuring, recovery after theft, etc. Guns are also commonly provided with serial numbers that can be used for similar purposes. Many consumer devices are also provided with serial numbers for purposes that include warranty protection and theft recovery.
A common problem with conventional methods is that the identification symbols can be readily located and/or removed. In the case of a gun, for example, the serial number can be removed by grinding or filing the barrel at a position where the serial number is located. A VIN can also be removed, altered, or replaced. With consumer devices such as e.g., a television or appliance, removal of the serial number may be as simple as locating the rear of the device and removing a tag or plate. Of course, once the identification symbols are removed, positive identification of the device for recovery after a loss or theft may not be possible. In addition, the deterrent effect against theft is reduced where an identification symbol can be readily removed or altered.
Conventional methods, such as e.g., acid etching and magnetic particle testing, do exist for the recovery of identification symbols such as serial numbers where such were placed externally on metal surfaces that have been filed or ground. However, these methods typically only allow recovery of identification symbols that were created by engraving or stamping and where only shallow grinding or filing has been attempted for removal. These methods are usually ineffective against machined or laser etched surfaces that do not have deep metal deformation or against surfaces where deep destructive filing or grinding has occurred.
Accordingly, a method for concealing one or more identification symbols into an object would be useful to not allow simple non-invasive removal of the symbols without the destruction of the object or disassembly of the object and loss of its usefulness. Furthermore a method that can be used to read or determine such identification symbols without destroying the object would be particularly useful. An object or device incorporating concealed identification symbols that can be later determined (e.g., read or revealed) through nondestructive testing would also be useful.